I did a diagnostic check on my 83 z-28 when it started to run like it was out of fuel, and got code 51. The service manual sent me through these steps; Check pin connectors on ecm and reset the ECM and perform the diagnostic test again. If code is still displayed, replace the PROM. Reset the ECM and perform another diagnostic check. If code is still displayed, replace the ECM. Here's my question:
If I put a new PROM in a "possibly" faulty ECM, will it harm the PROM?

 

I would suspect "wiring problems" or the ECM itself before the actual Memcal going bad. I would start off by going to a wrecking yard and trying another ECM first.

 

They used 3 different ecm's on the crossfires, mine was 1226026. Each ecm used a different prom. I've been following the steps on trouble shooting as outlined by the service manual. The $40 price tag of a special ordered prom vs. the $110 + price tag of a new ecm at this point looks more attractive. I should add that I discovered that someone had installed a super chip at some point, and that's all I know about that prom.